PROJECT SUMMARY The overarching goal of this proposal is to understand the contribution of the epithelium to esophageal inflammation and tissue injury through mechanistic studies of the key inflammatory mediator inhibitor of nuclear factor kappa-B kinase subunit beta (IKK?). The significance of this proposal lies in 1) the prevalence of esophageal disorders, which are a significant burden in the U.S. and throughout the world and 2) the central role of epithelial IKK? signaling in the regulation of diverse biological processes, such as inflammation, immunity, cell survival, and cell growth in numerous tissues and cell types. The PI is an early-stage investigator who is an expert in epithelial inflammation and injury, inflammatory mediators, animal models of disease, and epithelial biology, and is supported by a superb research team, complemented by expert collaborators. Here, we will take advantage of new mouse models and complementary in vitro systems utilizing 3D culture system to test the hypothesis that activation of epithelial IKK? signaling produces a pro-inflammatory, pro- proliferative, pro-angiogenic milieu that tips the balance towards the development esophageal diseases such as squamous cell dysplasia and cancer. To explore these processes, we will undertake three interrelated Specific Aims. In Aim 1, we will determine the functional interplay of STAT3 activation and IKK? signaling in the proliferative response of esophageal epithelial cells. This will be undertaken using mice with both active IKKb and STAT3 deletion, and three-dimensional (3D) mouse esophageal organoids. In Aim 2, we will define the role of epithelial IKK? signaling in epithelial-endothelial cell interactions during the transition from a normal state to esophageal dysplasia. Here, we will utilize a novel transgenic mouse model with esophageal epithelial IKK? deletion treated with 4-Nitroquinoline 1-oxide (4-NQO), and 3D vascular network formation assay. In Aim 3, we will investigate the role of epithelial IKK? signaling in the inflammatory response of esophageal epithelial cells during the transition from a normal state to esophageal dysplasia. This will be undertaken new transgenic mouse model of esophageal epithelial IKK? deletion that is treated with 4-NQO. These complementary approaches will confirm and extend the findings from our Preliminary Data and from our recent publication in Gastroenterology. Moreover, the proposed research will be supported by the superb and collegial intellectual environment and the exceptional resources and facilities available to the PI. We anticipate that these studies will provide insight into the factors that regulate normal esophageal epithelial homeostasis, the microenvironment, and the pathways that are disrupted in esophageal diseases, both benign and malignant.